The present invention relates to an antistatic hose for conducting gas, liquid, powder and the like, and more particularly to an antistatic hose suitable for conducting gas, liquid and powder charged by static electricity.
Heretofore, there has been a hose for conducting electro static charged gas, liquid, powder and the like, for example, as disclosed in Japanese Utility Model Patent Publication No. 30302/1984. This antistatic hose comprises a cylindrical flexible inner layer of insulation material which is wound by electrically conductive fibers, and an outer layer of flexible insulation material coated on the external peripheral surface of the conductive fibers from which a portion of the conductive fibers is exposed.
The antistatic hose of this prior art is intended for conducting a fluid having a pressure higher than an atmospheric pressure and is suitable, for example, for conducting synthetic resin or pellets supplied to an injection molding machine.
Accordingly, the hose of this prior art lacks sufficient strength against the force or pressure acting from the outside to the inside of the hose. When this hose is used in conjunction with a vacuum pump for evacuating a combustible gas, the hose is often collapsed by atmospheric pressure and therefore sometimes has caused an accident wherein the gas is exploded by the static electricity charge on the hose.